Questions about connecting mp3 player to stereo

[Parallel]

Hopefully these questions are easy to answer:
 
1) Is it normal to have to turn the volume up to 66% on my mp3 player when I connect it to my stereo system? I find it very quiet if I go below that level.
 
2) If I turn the volume up more, will it cause distortion? A friend of mine said that he turns his mp3 up to 100% and it doesn't cause any, but I've read different things online... a lot of people recommend setting it to 50%.

 

[cel4145]

When plugging an mp3 player up to a stereo, you want to run it near the highest volume where the mp3 player is not sending a distorted signal to the stereo, then use the stereo volume to control the volume. Where that volume point is will differ from mp3 player to mp3 player. It will also depend on if you have any bass or treble boost going on (best not to and control bass and treble with the stereo). Then, if you aren't using some kind of volume leveling feature on the mp3 player, some music will certainly play a lot louder than others.

So, sorry. Gotta use your ears

 

[Parallel]

When plugging an mp3 player up to a stereo, you want to run it near the highest volume where the mp3 player is not sending a distorted signal to the stereo, then use the stereo volume to control the volume. Where that volume point is will differ from mp3 player to mp3 player. It will also depend on if you have any bass or treble boost going on (best not to and control bass and treble with the stereo). Then, if you aren't using some kind of volume leveling feature on the mp3 player, some music will certainly play a lot louder than others.

So, sorry. Gotta use your ears

 
I guess one of my issues is that I'm not sure what distortion sounds like. I know that when I connect my laptop to my stereo system the sound quality is noticeably worse. The bass sounds really hollow and boomy and tends to overpower all the other instruments in my music. Is this what distortion sounds like?